Metabolic control of type 2 diabetes and prevention of its complications are related to management of blood glucose and other factors. Medication and lifestyle modifications are integral to most self-management plans; however, adherence remains a great challenge. Many patients have abnormal HbA1c, blood pressure and lipid values, and are at greater risk for complications. This proposal is to evaluate the effectiveness and costs of a tailored, telephone intervention to promote adherence in middle-aged and older adults with type 2 diabetes who are members of a union/employer-sponsored health benefit plan. The target population includes English-and Spanish-speaking individuals from the health plan database. Specific aims of the proposal are to test the hypotheses that 1) a tailored telephone intervention will significantly improve medication adherence compared to a standard care intervention; and 2) a tailored telephone intervention will significantly improve metabolic control measured by HbA1c compared to the standard care intervention. Aim 2a is to explore ways to link behavior change for medication adherence with lifestyle modification for diet and physical activity. Aim 3 is to conduct cost evaluations for the telephone intervention vs. standard care. The study design is a randomized, controlled intervention trial with masking; the individual is the unit of sampling, assignment and analysis. After eligibility is assessed and consent is obtained by telephone, patients will be randomized by gender and language preference (English or Spanish) to either the telephone intervention or standard care. Study outcomes will be medication adherence as measured from pharmacy records and metabolic control (HbA1c). A total of 556 patients with type 2 diabetes will be randomized, which will provide 80 percent power to detect a statistically significant difference in HbA1c of at least 0.3 percent, and over 95 percent power to detect a difference in filled prescriptions. Telephone surveys will provide data on self-care behaviors including diet and exercise, risk perceptions, and depressive symptoms. Cost data will be collected using standardized methods. Study results will inform implementation of practical, nurse-managed interventions to improve medication adherence and metabolic control in diverse, middle-aged and older, type 2 diabetes patients, while linking changes in medication adherence to lifestyle modification for diet and physical activity.